This invention relates to a gas chromatographic apparatus, and more particularly to a gas chromatographic apparatus with a gas calibration tube, a gas separation column, a gas sensor, etc.
When various gas components were detected through one detecting operation, for example, when gas concentrations of six gas components, e.g. H.sub.2, CO, CH.sub.4, C.sub.2 H.sub.2, C.sub.2 H.sub.4 and C.sub.2 H.sub.6, in a gas permeated through a polymeric membrane and stored in a gas calibration tube were measured in one gas separation column by gas chromatographic separation and quantitative determination, a very long gas separation column was needed with a very long detection time. To this end, a programmed temperature gas chromatography was needed. However, in the case of measurement where no such programmed temperature gas chromatography was available, a gas chromatographic apparatus as shown in FIG. 1 was needed for measurement. That is, a gas mixture consisting of, for example, 6 components, A, B, C, D, E and F stored in a gas calibration tube 1 through a valve 2 is introduced into gas separation columns 5a and 5b arranged in parallel with each other together with a carrier gas from a carrier gas source 4 through a switch valve 3, for example, a 6-way valve. The gas components separated in the gas separation columns 5a and 5b are introduced into gas sensors 6a and 6b, respectively, and their detections are amplified in amplifiers 7a and 7b and recorded in recorders 8a and 8b, respectively. In FIG. 1, numerals 9a and 9b are different gas separation fillers, i.e. different adsorbents with different adsorbabilities, filled in the gas separation columns, 5a and 5b, respectively. Numeral 10 is a gas flow rate controller. When gas sensors 6a and 6b are provided for two gas separation columns 5a and 5b suitable for gas separation, respectively, in this manner, 6 components A-F can be separated and measured, and the so-called chromatograph as shown in FIG. 2 can be obtained on recording papers on recorders 8a and 8b when the detections by gas sensors 6a and 6b are recorded on the recorders 8a and 8b. That is, the chromatogram shows outputs from gas sensors 6a and 6 b on the axis of ordinate and time on the axis of abscissa, and the results of separation and detection in one system of gas separation column 5a, gas sensor 6a, amplifier 7a and recorder 8a are shown by full line in FIG. 2, where, among 6 components, components A, B and C are distinctly separated and detected, whereas components D, E and F are not distinctly separated and detected. On the other hand, the results of separation and detection in another system of gas separator column 5b, gas sensor 6b and amplifier 7b and recorder 8b are shown by dotted line in FIG. 2, where, among 6 components, components A, B and C are not distinctly separated and detected, whereas components D, E and F are distinctly separated and detected. In a chromatogram the time up to a peak appearance is called "retention time" of a component, and utilized for qualitative determination of the component, and an area or height of the peak is utilized for quantitative determination of the component.
In the gas chromatographic apparatus shown in FIG. 1, components A-F can be separated and detected, but the chromatograms are obtained from each of the system of gas separation column 5a, and gas sensor 6a and the system of gas separation column 5b and gas sensor 6b, and thus the results cannot be obtained on one chromatogram in a continued state. Thus, connection of the two recorders to a data processing unit for calculating concentrations of gas components from the chromatograms, is a troublesome labor, resulting in complicated operation. In this case, two interfaces to the data processing unit are required for the gas sensors 6a and 6b, and this is quite uneconomical.